Automatic overdrive and transmission system



Dec. 18, 1956 o. H. BANKER AUTOMATIC OVERDRIYE AND TRANSMISSION SYSTBIFiled Sept. 8, 1951 5 Sheets-Sheet 1 mm YXQ@ INVENTOR.

Dec. 18, 1956 AUTOMATIC Filed Sept. 8, 1951 G. H. BANKER OVERDRIVE ANDTRANSMISSION SYSTEM 5 Sheets-Sheet 2 Dec. 18, 1956 o. H. BANKER2,774,256

AUTOMATIC OVERDRIVE AND TRANSMISSION SYSTEM Filed Sept. 8. 195] 5Sheets-Sheet 3 IN VEN TOR.

Dec. 18, 1956 o. H. BANKER AUTOMATIC OVERDRIVE AND TRANSMISSION SYSTEMFiled Sept. 8, 1951 5 Sheets-Sheet 4 l INVENTOR. @4cm 064 @laufe 1 BY/f//lz/f//fu/i/v? flu/m Dec. 18, 1956 o. H. BANKER 2,774,256

AUTOMATIC OVERDRIVE AND TRANSMISSION SYSTEM Filed Sept. 8, 1951 5Sheets-Sheet 5 IN VEN TOR.

United States Patent O AUTOMATIC GVERDRIVE AND TRANSMISSION SYSTEM OscarH. Banker, Evanston, Ill., assigner to New Products Corporation,Chicago, Ill., a corporation of Delaware Application September 8, 19571,Serial No. 245,721

16 Claims. (ci. 744740) The present invention relates to improvements inan automobile drive system or assembly featuring the cornbination in animproved manner of an improved planetary type overdrive unit, a manuallycontrolled multiple speed transmission, and a Huid coupling or relatedtype of clutch device. The invention has as its general object theprovision of a combination of the above sort in which it is possible toobtain, fully automatically, a multiplication of the number of speedratios normally aforded in a conventional installation involving relatedunits, and, moreover, to do this in a fashion which permits manualoperation of the transmission at all times.

A more specific object is to provide an installation including aplanetary type overdrive unit associated in a novel manner with amulti-speed transmission, preferably of the synchromesh type, and with alluid coupling or equivalent coupling unit for improved conveniences andadvantages in operating a vehicle featuring the installation,particularly when the vehicle is not moving.

Yet another object is to provide an installation as set forth in thepreceding paragraph in which operation of certain automatic controlmeans for the overdrive unit is automatically effected in part bymanipulation of the usual selector of the transmission and in part bymanipulation of the usual throttle pedal of the vehicle.

It is another object of the invention to provide a combined planetaryoverdrive-change speed transmission assembly of the foregoing characterwhich has Vimproved provisions for substantially automatically changingfrom a low speed direct ratio in the planetary unit to a higher speedoverdrive ratio, preferably in which the time for changeover in ratio isat all times under the control of the operator of a vehicle powered bythe assembly, rather than being eifected solely through an arbitrarilyacting governor or equivalent element.

A still further object is to provide an assembly of the above sortfeaturing an improved overdrive unit employing planetary, sun and orbitmembers in conjunction with an overrunning clutch, in which a low speedratio is obtained by a direct shaft drive through the clutch and theoverdrive train is through the planetary members while the clutchoverruns, together with improved means for controlledly, and primarilyautomatically, governing these actions in accordance with the speed oftravel of the vehicle.

Yet another object is to provide a planetary overdrive unit of the abovetype in which control of operation of the overdrive unit is eifected byan improved hydraulic system, featuring an improved pressure intensifieror booster arrangement enabling the unit to be operated by a lowpressure hydraulic source.

Another object of the invention is to provide, in a hydraulicallycontrolled overdrive system, preferably of planetary overrunning clutchtype as set forth above, improved means for supplying operating liquidfrom a low pressure source to a hydraulic unit which controls theoverdrive, including a supply and booster unit by which the hydrauliccontrol for the system is initially operated i ice under the lowpressure of the source, such as the usual engine lubricating pump or asmall pump specially built into the installation, and is nally operatedunder a substantially increased pressure supplied by the booster innovel manner.

Yet another object is to provide an improved hydraulic' supply andbooster unit of the sort referred to above. I

A more specific object is to provide a hydraulic control unit for aplanetary type overdrive unit or the like, including a solenoid operatedvalve controlling the flow of operating fluid from a low pressure sourceto a mechanism which operates the unit, and a hydraulic booster plungerand cylinder associated with the valve and mechanism in an improvedmanner to materially increase the pressure acting upon the latterfollowing initial operation of the operating mechanism directly from thelow pressure source. v

A still further object is to provide a system or installation asdescribed in the preceding paragraph, which features an improved,electrical control arrangement for the hydraulic operating unit of theoverdrive, whereby the placing of the latter in overdrive ratio inresponse to operation of a governor is primarily subject to control bythe operator of the vehicle, rather than being arbitrarily and solely inaccordance with speed of travel of the vehicle.

The foregoing statements are indicative in a general way of the natureof the invention. Other and ymore speciiic objects will be apparent tothose skilled in the art upon a full understanding of the constructionand operation of the device.

Two embodiments of the invention are presented herein for purpose ofillustration and it will be appreciated that the invention may beincorporated in other modified forms coming equally within the scope ofthe appended claims.

In the drawings,

YFig. l is a view mainly in vertical section through the axis of a uidcoupling-planetary overdrive-multiple speed transmission system inaccordance with one embodiment of the invention, showing particularlydetails of construction of the overdrive unit thereof;

Fig. lA is a conventionalizedrview in elevation showing in a general waythe improved arrangement of fluid coupling or clutch unit, overdriveunit and transmission unit which is contemplated by the invention, thisview being partially broken away at the transmission unit to showselector elements thereof;

Fig. 2 is a view in transverse vertical section, approximately on line 22 of Fig. l, through a portion of the planetary overdrive unit, showingthe arrangement of a hydraulic brake actuating plunger for the latterand an intensifier or booster unit for the actuating plunger; i

Fig. 3 is a fragmentary view in transverse vertical section through thebooster unit referred to;

Fig. 4 is a fragmentary View in axial section through a coupling drivenoverdrive-transmission arrangement in accordance with a modified,simplified and more compact adaptation of the invention;

Fig. 5 is a fragmentary elevational view of schematic character showinga hydraulic pressure supply and control arrangement fora brake actuatingpiunger controlling the overdrive unit shown in Fig. 4 (also applicableto the installation of Figs. l and 2), this view being partially brokenaway and in vertical axial section;

Fig. 6 is a view which is partially schematic and conventionalized,illustrating the hydraulically operated overdrive unit of Figs. 4 and 5as operatively associated with an electrical, governor controlledoperating system for that unit;

Fig. 7 is a fragmentary view in axial section showing a detail of thehydraulic booster and lactuating device which is further illustrated inFigs, 5 and 6;

`4Fig. 8 is a somewhat conventionalized view in side elevationillustrating a proposed device for automatically actuating aV controlswitch of a governor regulated solenoidcircuit, shown in Fig. 6, throughmanual operation of a selector or selectors of the transmission unit ofthe present system; f i Fig. `9 is a plan view showing certain cam andlever operating elements to the device of Fig. 8, and indicating themanner in which the same are manipulated in the shiftingof gears todierent ratiosyto correspondingly control the governor circuit; and

Pigs. and 10A are schematic views, which may be considered to be insection on line 10-16 of Fig. 8, Vfurther illustrating the operation ofthe switch control `meansin various positions of the transmissionselector levers. f `Referring to Figs. l and 1A Yof the drawings, thepresent system Vor assembly is made up of three main components. Thefirst of these is a uid coupling unit 10 of generally conventionalcharacter, having a ange 11 at 1 theleft hand side thereof which isadapted to be attached to a crank shaft angeor spider (not shown) bybolts applied to tapped holes 12. The second unitV is a-hydraulicallycontrolled, planetary typeoverdrive unit, generally designated 13, andthe third unit is a 'conventionalpmanually controlled three-speedsynchroan improved one enabling operating advantages over existingsystems as will be described. If desired, uid coupling 10 may bereplaced, in either of the illustrated embodiments, by equivalentcoupling means, such as a centrifugal clutch, to further reduce the costofy the Y'system, as will be described.

' shaft is Vis splined at i7 to the extended hub is of an output member19 of the planetary overdrive unit 13.V

The refereneenumeral 21 appearing toward the left hand side of Fig. ldesignates a tubular output shaft of the YHuid coupling ,unit 1li. It isequipped with an elongated, axiallyY extending hub 22, and is pilotedonya bearing 23 mounted internally of coupling flange 11.v Hub 22 isprovided with a standard carbon type seal 24 and compressiblemetalbellows 25 or its equivalent toseal the hub from the atmosphere.vHub 22 is provided with internal splines 26 which drivingly engage thesame with va main planetary shaft 27; and this shaft has a reduceddiameterleft hand `end ZS'Which is piloted by an end cap 29and a needlebearing 29 Within the bearing 23.

Theopposite endmof main planetary shaft 27 is also reduced in diameterat 30, and is piloted by a roller bearing 31 Within the tubular inputshaft 16 of synchromesh transmission unit 14.

A brake drum 34 is keyed to main shaft V27 externallyV of uid coupling10 and within a bell housing 33 kwhich .encloses operating parts of theplanetary overdrive unit 13. nut 35 is applied to the shaft for apurpose to be described. The drum 34 has an axially extending hub 36Vwhich's journaled by a bushing 37 in a shaped pump housing 38 locatedwithin theV axially extending rim of the drum 34.

The reference numerals 4t), 46' designate the gear and 'rotor'of aninternal gear pump mounted concentric with shaft 27, andthe referencenumeral 41 denotes an end member which completes the pump housing. Thisend member surrounds an enlarged integral shoulder ,42 on Yshaft 27, andnut 35 acts to urge hub 36 of drum 34 and the pump rotor 4G' against endshoulder 42. An appropriate seal 43 seals the interior of pump housing 438, to which hydraulic pressure liquid is admitted through an intakeport 44. Y

Housing 38 has a radially extending flange 45 of substantial size and anintegral annular shoulder 46 on'flange 45 serves to pilot the pumphousing within the left hand end of a cylindrical bore 47 of bellhousing 33. Flange 45 is iixedly secured to housing 33 by bolts 48.

A sleeve 50 surrounds `main planetary shaft 27 immediately to the rightof the pump housing 38 and shaft shoulder 42, the sleeve being journaledby a ball bearing 52 in an integral right hand extension 53 on pumphousing flange 45. Sleeve 50 is externally splinedV at 5S to key thesame to a drum 54. it alsoY carries a sun gear 56 meshing with planetarypinions 57 which are rotatably mounted oy pins 57 on a planetary carrier5S. Carrier 53 is splined at 59 on a reduced diameter intermediateportion of shaft 27. APlanetary pinions 57 also mesh withthe internalteeth of a ring or orbit gear 61, and the teeth of this orbit gearengage external teeth 62 forme'dron the previously describedvoutputmember 19 of planetary overdrive unit 13. Y Y

Planetary carrier 58 is drilled at 63 for'lubrication and its outerperipheral surface at the right hand side thereof is hardened to serveas an inner race of a sprag type clutch, the hardened sprags of whichare designated Y 65. The outer race of the clutch is constituted by thevmachined and hardened innerrperipheral surface of the planetary outputmember 19. f Y

A snap ring 67 holds the planetary carrier 5S axially in place on shaft27 to which it is splined. Likewise snap rings 68 and 69 hold lower ballVbearing 52 in place ou sleeve'SG. A still further snap ring 70 holdsthe orbit gear 61 with relation to the output member 19 of theoverdriveunit.

As stated above, the output memberv 19 -is directly f splined at 17 tothe manually controlled synchromesh transmission unit 14. input shaftp16 of this unit is mounted by a ball bearing 72 in the casing 75V oftransmission unit V14, which casing is properly located with respect tothe bell housing of planetary unit 13 by engagement'with a plate 73 inthe end wall of the bell housing 33. The outside diameter of plate 73 isaccurately machined to fit within the right hand end bore 74 of the'bell housing.V Y

A roller bearing 76 in the bore of tubular transmission shaft 16supports the output shaft 77 of the transmission 14, lwhose input pinion15 is'carried on the exterior of shaft 16. A spacer ring 78 separatesthe two bearings 31 and 76 for the main planetary shaft 27 andtransmission output shaft 77, respectively, and a snap ring 79 serves tolocate the input shaft 16 and pinion 15 in proper relation to the ballbearing 72. i

An overdrive controlling brake bandV 8@ is mounted in the bore 47 ofbell housing 33, in surrounding relation to the drum 54, and thefunction of this brake band will be hereinafter described. A brake band81 is also positionedY about the rst described kdrum 39.

When fluid coupling 10 is driven by the engine its output shaft 21 willdrive main shaft 27 through the splined connection 26. Pump impeller 4Qis thus :driven to commence building up hydraulic pressure for use atthe place through splines 17 and inputpinion 15 of the latter. This isthe line of power transmission for a low speed phase Vofropzeration ofplanetary Voverdriveuuit 13.

. Y In order to initially engage the synchromeshV transmission,particularly in the event the vehicle was in high vgear or othergeartrain when stopped, the main shaft 27 `must be held from a normalfloating movement due to hydraulic action in' the coupling 1G. Ofcourse, if 'a centrifugal clutch is' substituted for the uid couplingthis tendency is not present, Vso that the means to counter-v act the`same in the illustrated form, namely drum l34 and brake band 81, may beeliminated. In suchV case lockup' of the centrifugal clutch isaccomplished at the time the overdrive band 81B is applied.

Only very low torque is required to restrain the aforesaid oating actionduring the idling period of the engine. By actuating a solenoidcontrolled valve such as is shown and described inmy Patent No.2,353,137 of July l1, 1944, and 2,482,573 of September 20, 1949, orequivalent means, from any convenient place adjacent the operator, thebrake band 31 is applied to drum 34 and rotates the shaft 27 slightlybackward in relation to the direction of torque on unit 1t). The bandthus holds the drum from rotation and relieves all of the drag torque onthe gear teeth in the circumstance noted.

After engagement of the low gear train of the transmission takesplace,band 81 is released, whereupon pinion will drive the vehicle in lowspeed. The overdrive constitutedrby sun gear 56, planetary pinions 57,orbit gear 61, and the splined connection of the latter to output member19 is inactive.

ln order to bring the unit 13 into overdrive, brake band Si? is appliedto drum 54. This is preferably accom plished by means of a conventionalelectric governor driven by output shaft 77 at the rear end oftransmission 1li, as shown in Figs. 1A and 6 and hereinafter furtherdescribed. Through means of this type, and at a given predeterminedspeed, an automatic overdrive actuating mechanism, also to be described,will be energized to apply band 89 to the drum 54. When this occurs, sungear 56 haltsl and planetary action results. Orbit gear 61 and outputmember 19 to which it is splined now overrun the sprag elements 65 andtransmission input shaft 16 is rotated at a higher rate of speed.

In the event overrule of the overdrive through the planetary system isdesired, a switch which controls the circuit for the governor actuatedsolenoid may be broken oy depressing the accelerator pedal past its wideopen position. This will de-energize the actuating mechanism, referredto above, controlling brake band Si), whereupon clutch sprags 65 willresume. a direct driving relation to output member 19. Just as soon asthe accelerator is allowed to return, brake band 39 will be re-engaged,assuming a proper speed obtains, and overdrive resumed.

The automatic overdrive brake actuating mechanism referred to above isconstituted by a solenoid controlled hydraulic valve governing pressuresupplied by pump r0- tor 41B. The latter is at this time running fastenough to generate all the pressure needed, which, due to the furtherprovisions to be described, is a relatively low one.

With the foregoing explanation of the general operation of the proposedplanetary overdrive and transmission system, the automatic provisions,involving a solenoid controlled valve, for eEecting hydraulic control ofthe planetary system by actuating brake band 86, may now be considered.

In this connection, it is desirable that a low pressure hydraulic supplybe used for easy maintenance of the equipment, quiet operation of thesame, and diminished power consumption. Hydraulic transmissions in useat the present operate with a pressure of upwards of 80 to 150 pounds,which is as low as has been found practical. However, the illustratedsystem operates on a much lower oil pressure and, in employing ahydraulic servo-mechanisrn' which bears directly on the brake band Si),eliminates the need for levers and/or links to extend the travel of ahydraulic piston associated therewith. As a result periodic adjustmentof the band for Wear is unnecessary. The hydraulic control systemreferred to is illustrated in Figs. 2 and 3 of the drawings.

As shown in Fig. 2, the brake band Sil is mounted snugly in the bore 47of bell housing 33. One end thereof has a shaped shoulder 83 ixedthereonwhich rides the face of a block 84 mounted in fixed relation to thehousawa-256 ing. The opposite end of the brake bandis provided with anarcuate seat which straddles apin 86 carried byv a plunger rod 87. Acoiled, plunger return spring S8 surrounds an extension of rod 87, thespring acting between the seat S5 and the plunger guide rod 8.9.VAplighhterncoil spring SS acts to spread the ends of *the band andafford proper clearance between the band and drum 54. Proper initialclearance may be had by an adjustment of'block 84,'by the use of a shim,or the like. Rod 87 abuts a disk type plunger which slides in a cylinder91v formed in the bell housing, this plunger being sealed with relationto the cylinder Walls by means o f an 0ring 92 seated in a groove aboutthe periphery of the plunger. A pressure chamber 93 in cylinder 91, tothe right o f plunger 90, has a right angle bore 94 opening theretoandto an enlarged counterbore 95 in which a cylinder intake control member9x3 is disposed. The bore 94 and` an axially aligned bore 97 of the samediameter in member/96 slid` ably receive a reduced diameter. booster Yorintensifier plunger 93. The latter has an enlarged piston head.k 99 onthe upper end thereof. Piston head 99 slides in enlarged, verticallydisposed booster cylinder 161). A coil spring 1%1 acts between the head99 and the intake meinber 95 to urge 'the former upwardly, and a reduceddiameter upper extension 162 on the head limits upward movement ofplunger 93 in cylinder 160. This extension is an integral part of thepiston head 99.V Y

Intake control member 96, in which the plunger 98 is slidably guided, isheld in place in counterbore 95 by a snap ring 1153. The lower end ofmember 96 is internally relieved at 1:14 to provide an annular groove inwhich anY 0-ring 105 is disposed for sealing engagement with the lowerend of booster plunger 9S. The loWcr end4 of the member is likewiseexternally relieved at 166 to provide an external groove receiving anO-ring 107 which seals the member 95 externally with relation tocounter-bore 9S. A further enlarged internal annular groove 108 isformed in intake member 96, opening inwardly to the bore 97 thereof, andradial ports 169 communicate this groove with an external annular groove110 in the member. Groove 1111 in turn communicates with a passage 111in the bell housing 33.

As shown in Fig. 3, the passage 111 is in direct communication with ahorizontal cylinderV or plunger bore l112 formed in the housing or in axedly associated part, and a plunger valve 113 is slidably received inbore 112. Valve 113 is urged by a coil spring 114 to engage its reducedconical forward nose 115 with a port 116Uwhich opens laterally to theupper portion of the booster cylinder 19?. A plug 117 held in place bysnap ring 11S closes the plunger valve bore 112, and O-ring 119 appliedto the plug seals bore 112 from theV atmosphere. p

The space between plunger valve 113 and plug 11 7 is suitablycommunicated by a duct (not shown) with an oil reservoir or sumpsupplying oil to the intake 44 of pump housing 38, shown in Fig. 1. Thistakes care of the drainage of oil accumulated behind the valve.

A passage 129 in alignment with passage 111 communicates plunger valvebore 112 with an elongated cylindrical valve chamber 121 disposedhorizontally thereabove, and a cylindrical valve spool, generallydesignated 122, is slidably mounted in chamber 121. The spool is urgedtoward the left by a coil spring 123 acting between an enlargedcylindrical portion124 of the spool and an abutment and guide plug 125fixed in the right hand end of bore 121. A stem 126 secured totheenlarged valve spool portion 124 passes through the guide 125 and issecured to the armature of an electrical solenoid, generally designated127.

Valve spool 122 has an enlarged forward nose 128 of axial lengthapproximating that of portion 124, a somewhat longer intermediate barrelportion 129, and a shoulder 13u of reducedrwidth between portions 124and 129. These portions divide the spool into three-grooves, namely arst groove 131 of relatively slight axial width, an in-V termediategroove 132 of extended axial width, and a third groove 133 ofintermediate axial width. The valve spool has a hollow axial bore 134and a small opening 135 communicates the rst groove 131 with thisinternal bore. Groove 131 is adapted to communicate with an exhaust port136 which opens from the valve spool chamber 121 to the upper portion140 of plunger cylinder 100. See Figs. 2 and 3. The intermediate,axially elongated groove 132 opens to the exterior of the housingthrough an external, pressure delivery port 137 .Y The third groove 133is communicated with plunger valve bore 112 by the passage 120 describedabove, while a radial hole 138 in the valve spool communicates thegroove 133 with its internal bore 134.

The external port 137 described above is a hydraulic pressure deliveryport and it is connected by a suitable pressure duct or line 138 withthe discharge of the gear pump (Fig. l). Valve spool 122 is shown in anexhaust position in Fig. 3 of the drawing, in which the longest groove132 registers With'the delivery port 137 and the groove 131 registerswith "port 136 opening to the pressure chamber 140 above the head 99 ofbooster plunger 98. Groove 133l then is in communication with passage12) and plunger bore 112, and the lateral port 116 to p ressure chamber140 is sealed olf by the nose 115 of plunger valve 113. An exhaustchamber 141 in valve spool bore, at the left hand end of spool 122, iscommunicated by a passage 141 with'the sump ofthe pump, so that fluidexhausted from chamber 149 may pass through passage 136, groove 131,radial opening 135 and internal bore 134 of the valve spool to the sump.Fluid from brake actuating plunger chamber 93 exhausts, in this positionof the parts, through bore 94, intake member 96 and radial passage 109and groove 114i of the latter, passage 111, plunger valve bore 112,passage 120, groove 133 and radial hole 13S to the internal bore 1340ispool valve 122, whence it also passes out through the left hand end ofthe spool to exhaust chamber 141 and to the sump. f y

The brake band 30 is set'v against drum 54 in a rrn and rigid manner,underra multiplicationof the available hydraulic pump pressure, when thetransmission driven governor referred to above causes solenoid 127 to beenergizedthus drawing valve spool 122 to the right, as viewed in Fig. 3,against the resistance of spring 123. This causes the enlarged, lefthand end portion 128 of the spool to close oi the exhaust port 136 frombooster cylinder pressure chamber 140. At the same time the passage 120opening plunger valve bore 112 to valve spool chamber 121 is removedfrom communication with spool groove 133 and radial exhaust port 138 andis placed in communication with the intermediate, elongated groove 132.Groove 132 is in constant communication with the pump delivery port 137.

Low hydraulic pressure is nowV communicated from pump housing 38 throughconduit 13S, port 137, groove 132, passage 120, plunger valve bore 112,passage 111, and through the intake member 96 to plunger pressurechamber 93. This pressure,v although much less than that commonlyresorted in existing installations, is suflicient to shift plunger 9i)Vto the left, as viewed in Fig. 2, and to bring the brake band 89 intocontact with drum S4.

Naturally, as plunger 90 is moving to the left the pressure in chamber93 reduces until the travel of the plunger t stops upon initialapplication of the brake band to the drum. When the plunger is fullystopped, the pressure in chamber 93, passage 111 and plunger valveV bore112 again rises to full pump pressure. ri`he spring 114 which controlsplunger valve 113 is chosenof such force that it holds the plunger valve113 in closing relation to the lateral port 116 to booster cylinderpressure chamber 148 until the full pump pressure is again reached. Whenthis takes place, plunger valve'113 moves to the right, compressingspring 114 and opening port 116'to passage 111.' Pump pressure Vis noweffective in chamber 140 lower end of plunger 98 passes the internalO-ring 105 l' (Fig. 2), the chamber 93 becomes absolutely sealed againstloss of pressure past the intake ymember 96. Accordingly, as the lowerend of plunger 9S continues to advance into bore 94,- thek pressuretinchamber 93 rises abruptly. v Y

Plunger 90 isnow urged toward the left under a multiplication of forcerepresented Vby the differential in area of the booster plungeritselfand its enlarged piston head 99. This ratio is predetermined inthe design of the system whereby any desired pressure in chamber-93 maybe attained. Since iluid cannot escape from chamber 93, and sincepressure chamber 140 is constantly subject to the pump pressure, thehigh pressure in chamber V93'is maintained just as long as the circuitfor solenoid 127 is maintained by the engine governor. The pressure risein chamber 93 is sufficiently gradual to give a smooth retarding actiononV drum 54 and then to hold the drum from rotation. Y

Upon de-energization of solenoid 127, spring 123 will return the spool122 to the left, communicating exhaust port 136 o pressure chamber 140,and passage 111, with the sump through the respective iluid ow lines,both including the internal bore'r134 of spool 122, as described above.Plunger 98 again rises and plunger 90 releases brake band in a mannerwhich is apparent.

A drop of pressure in .chamber 140 and passage 111 occurs immediately,accompanied by a drop of pressure in plunger bore 112, so that theplunger 113 returnsV to sealing engagement with the pressure'supply port116. Even though port 116 is closed, the bleeding of pressure liquidthrough port 136 and spool bore 134 is sufficiently rapid to insurequick disengagement of the brake band 80 from the drum, unimpeded bydashpot effect in booster cylinder 106.

The above described method of intensifying a low presf sure controlliquid to produce a force sufficient for holding a brake band in holdingrelation to a control drum relies upon the principle of building uphydraulic brake band actuating force, and then maintaining the forceonce the desired Value has been attained. This is distinguished from theprinciple of replenishing high pressure from time to time. Plunger willunfailingly bring the brake band 80 to operative relation to drum 54 andthen build up and maintain drum holding force, regardless of the extentof wear on the band taking place over a long period of operation. Noadjustment of the baud is necessary to takeup for wear. Once the chamber93 is lled with low pressure operating fluid, plunger 90 will comi menceto move, regardless of the volumetric capacity at its right. Once band80 has been brought into engagement with the drum, the describedmultiplication of force takes place regardless of the distance which hasbeen traversed in bringing the brake band into contactwith the drum.

ln the embodiment of the invention illustrated in Figs. 4, 5, 6 and 7 ofthe drawings, a generally similar hydraulic intensifier or boostersystem is employed. Modification of certain mechanical features :of theoverdrive unit is resorted to in the interest of'increased compactnessand re-` duced cost of manufacture. To the same ends, a separate pump,built into the overdrive unit and driven from a Y coupling or clutchthrough the main planetary shaft, has been omitted.V Control of theoverdrive vunit of this modified form relies upon the hydraulic pressureof the engine lubrication system.

Referring to Fig. 4, the engine driven fluid coupling A planetarycarrier G is keyed at 15,1 to theY shaft 145 and journals planetarypinions 152 which mesh with teeth 153 formed on an elongated extensionof sleeve146. Planetary carrier 150 carries a second brake drum 154 inxed relation thereto, the drum being shown as mounted on pins 155 on theplanetary carrier upon which the planetary pinions 152 are rotatablymounted, in this case by a roller bearing 156. Drum 154 is shapedso.that 'it may be telescoped axially Within the axial overhand of drum14, and the planetary carrier and associated parts to be described, areaxially telescoped within drum 154.

A ring or orbit gear 157 meshes with planetary pinions 152 and issplined at 15S to a planetary output member 159. Here again, theplanetary carrier 150 and output member 159 serve as inner and outerraces, respectively, for the sprags 169 of an overrunning sprag typeclutch, the relationship of parts being similar to that illustrated anddescribed in connection with Fig. l. Output member 159 is splined at 161to the tubular input shaft 16' of a conventional three speed synchromeshtransmission 14', such as that preferred to in connection with the lirstembodiment. The input pinion of this transmissionvis formed integralwith shaft 16 and is designated 15. The right hand end of the main shaft145 is roller bearing journaled at 164 in the interior ot tubular shaft16', as is an adjacent end of the transmission output shaft, designated77 since it corresponds to shaft 77 of Figs. l and 1A. Otherwise themounting of all parts in this zone is similar to that shown in Fig. l,hence similar reference numerals are employed to designate the same. t

An overdrive control brake band 166 is disposed for engagement with drum148 and a smaller band 167 is similarly adapted to engage drum 154.These brake bands are snugly received within a bell portion of a housing168 of the overdrive 13 in which a llange or wall 169 associated withsaid housing is piloted at 170. The functioning of the arrangementillustrated in Fig. 4 is similar to that shown in Fig. l, insofar asattainmenttof low speed and overdrive ratios is concerned, hence thedescription need not be duplicated in this regard. It is to be notedthat considerably increased compactness results from the elimination ofa shaft driven pump, together with pump housing and sealing provisionsembodied in the form of Fig. l. Preliminary stoppage of drum 154 iscaused by application of band 167 to drum 154 as described above. Theoverdrive phase involving application of band 16610 drum 148 is alsoarrived at as described in connection with Fig. l.

Referring to Fig. 5, the source of hydraulic pressure for control andactuation of the overdrive unit of Fig. 4 is, as stated above, theexisting engine driven lubrication pump, diagrammatically illustrated inFig. 5 and Ydesignated generally by the reference numeral 172,. Thispump discharged through a passage 173 to an elongated cylinder 174 inwhich a valve spool 175 is slidably mounted. The spool is urged to theright, as viewed in Fig. 5 (and also in Fig. 6), by a coil spring 176which acts between an enlarged end portion 177 on the spool and a fixedabutment surface. A stem 178 on the valve spool 175 extends to the'leftand is secured to the armature of a solenoid (Fig. 6) which is generallydesignated 179.

Fig. 5 illustrates the valve spool 175 in its position when solenoid 179is de-energized, i. e., for direct4 drive operation of unit 13'. In thisposition, pump delivery passage 173 delivers liquid under pressure to agroove l180 in the valve spool located between enlarged portions V181and 182 of the latter. A similar groove 183 is formed between theenlarged portions 177, 181 of the spool, the'latter having a radial hole184 communicating at this zone with its hollow bore 135. An exhaust ordump .chamber 1876, between the enlarged forward portion 182 of thespool and the end of spool cylinder174, communicates through an exhaustpassage 187 with the sump of the pump 172,

schematically shown and designated 1.88. An intake con-A duit 189 forthe pump extends into this sump.' The part of valve spool cylinder 174to the rear, or left hand side, of enlarged spool portion 177 is alsocommunicated. with sump 18S through an exhaust passage 190. s

Liquid under normal pump pressure is supplied to a booster type brakeband actuating device for planetary unit 13 which is very similar tothat shown in Figs. 2 and 3, and will be hereinafter described only inageneral way. For this purpose, a passage 191 is provided' (see Fig. 5)which opens to valve spool cylinder 174 adjacent the spool groove whenthe spool is in its illustrated pressure dumping and brake releasingposition. Groove 18e at this time registers both with pump deliverypassage 173 and with passage 191. Further passages 192, 193 are providedwhich also open to spool cylinder 174,'v the former to a zone of thecylinder adjoining spool groove 183 in which zone radial exhaust hole184 is now located) and the latter to the space 194 at the rear of spoolportion 177. Space 194 communicates with exhaust passage 19u asdescribed above.

Passage 191 leads from cylinder 174 to a portion or chamber 195 in thebrake actuating cylinder 196 (Fig. 6) at the rear, or right hand side,of its plunger 197. Passage 192 leads through a passage 111 (shown inFig. 7 and corresponding to the passage 111 of Figs. 2 and 3) to apressure intake member (not shown) which corresponds to the pressureintake member 96 of those figures. lt leads thence through a radial bore(similar to bore 94) which opens to a pressure space in cylinder 196 onthe left hand side of piston 197. l

The lower end of an intensifier or booster plunger 198 is slidablyreceived in the last named bore in the fashion illustrated in Fig. 2.Details of this fluid intake arrangement for the brake actuatingcylinder 196 are not illustrated in Fig. 6 of the drawings in order tosimplify the disclosure. However, they are the sameV as those shown inFig. 2 of the drawings; and their operating relationships are the same,so that reference may be had to Fig'. 2 in this connection.

Passage 193, lan exhaust passage, is communicated with the upperpressure chamber 199 of a booster or intensifier cylinder 200 whichslidably receives the enlarged piston head 291 of plunger 19S. Hereagain the arrangement is similar to that of Figs. 2 and 3.

Yln the brake release position of the valve spool shown in Fig. 5,liquid is supplied from sump 18% through conduit 9 to pump 172 and isdischarged by the pump through passage 173 to cylinder 174, whence itexits through groove 18; and passage 191 to space 195 in brake actuatingcylinder 196. As illustrated in Fig. 7, passage 192 leads to a plungevalve arrangement shown in Fig. 7, which is similar to that shown inFig. 2, hence corresponding parts are designated by correspondingreference numerals, primed. These include a bore 112 towhich passages192 and 111 open, a port or passage 116 at the end of the bore whichopens laterally to' pressure chamber 199 of booster cylinder 290, and aspring urged valve plunger 113 whose nose controls port 116', as in theform of Figs. 2 and 3. Further description of the plunger arrangement isdeemed unnecessary.

The passage 111' connects plunger bore 112 with a liquid intake memberassociated with booster plunger 198 in a manner which, as stated above,is like that of Fig. 2.

Referring to Fig. 6, n rearwardly disposed rod V2535 on l' the brakeactuating plunger 197 has a collar 2116 secured thereto and isrearwardly guided in a fixed housing member 2217. A coil spring 293 actsbetween the rear of cylinder 196 and the collar 266 to urge the plunger197 to the right. The rear end of plunger rod 205 abuts the enlarged`arm of a lever 2119 which is pivoted at 210 on a part of the housing.' Arounded seat on lever 299 receives a thrust'pin 211 pivoted on one endof the brake band 166. 'Ihe opposite end of that band engages an.

adjustable abutment pin 21?: `on the housing. n Y Y l A Under theconditions described, the solenoid 179 is engine.

1l de-energized and brake actuating plunger 197 is urged toward the leftby mild hydraulic pressure in the-right hand cylinder portion 195. Thispressure is transmitted by the pumpr172 through passage 173, spoolgroove 18) andpassage 191. Pressure chamber 199 in booster cylinder 200is voided through passage 193, rear spool cylinder space 194 and passage191i to the sump 188. The left hand side of brake cylinder 196 is voidedthrough passage 111', plunger valve cylinder 112', passage 192, sppolgroove 183, radial spool hole 184, internal spool bore 185, exhaustspace 186 and passage 187 to the sump. Brake band 166 is thus positivelyreleased from drum 148 and the roverdrive unit 13' is inV low gearposition.

When solenoid 179 is energized, valve spool 175 is Vdrawn to the left,as viewed in Fig. 5. This causes its enlarged rear portion 177 to sealpassage 193,- hence sealing off pressure chamber 199 in booster cylinder2%. The intermediate enlarged portion 181 passes across passage 192,thereby cutting oit its communication with exhaust groove 182 andexposing passage 192 to groove 180 in the valve spool, which groove isat all times open to pump delivery passage 173. Likewise, the enlargedportion 182 seals oi groove 181i from passage 191 and exposes the latterto exhaust space V136 and sump passage 187.

In this position of the valve spool, the rear space 195 of brakeactuating vcylinder 196 is exhausted through passage 191, space 186 andpassage 187, while the spaceV on the opposite side of plunger 197 ispressurized in the fashion described above. The ensuing operation issimilar to that described in connection with the embodiment of-Figs. l,2 and 3.

The modilied assembly illustrated in Figs. 4 7 enables a vehicle towhich it is applied to be started by pushing in the event of a batteryfailure, without involving the locking up of mechanisms or clutches. Theparts are so arranged that when the engine and engine driven pump 172are dead the pressure in cylinder 196 is forced back through the pumpunder the force of the relatively powerful spring 208 on plunger 197.This spring is strong enough to hold overdrive control brake Vband 166sufciently for transmission of adequate torque to crank the Accordingly,with a dead engine the band 166 is always set, so Vthat when the vehicleisV put in direct drive through transmission gear 163 and then pushed,the overrunning unit comprising sprag and clutch race members 150, 159and 161! will allow the orbit gear 157 toract as a driver. Underthesercircurnstances the planetary arrangement becomes anunderdrive,1rather'than an overdrive. Shaft 145 cranks the motor throughfluid coupling at a slight reduction, as compared to direct drivethrough unit 13.

As soon as the engine starts, valve spool 175,` being in the positionillustrated in Fig. 5, willY direct hydraulic pressure into passage 191and the right hand chamber 195 of cylinder 196 (Fig. 6). This willretract plunger 197 against the force of spring S and release band 166from drum 14S. So long as the engine continues to run at a speed lessthan the critical governor speed, the drive will be direct through shaft145, locked clutch elements 153, 160, 159 and transmission input shaft16 to the rear axle of the vehicle.

A governor-controlled shifting to overdrive has been referred to above,and a suitable arrangement to this end is illustrated in Fig. 6 of thedrawings, to which reference is now directed. This governor operationcontrols energization and de-energization of a solenoid, which in turncontrols the shifting of a valve spool. Obviously since this may beeither the spool 122 of the adaptation vof Figs. 1 3, or the spool 175of the adaptation of Figs.

4-7, 'the electrical provisions illustrated in Fig. 6 are equallyadaptable to both of these embodiments. In the interest o f simplicitythey have been illustratedY only in the `last named ligure.

Vit is desirable for the operator of Ythe-'vehicle to have some choiceor discretion in deciding when and where the overdriverunit is to beplaced in overdrive position, rather thanY being at Vall timesarbitrarily controlled in this' matter by the action of a governorcoming into operation at a definite, set speed. In other words', it isdesirable that a minimum limit for overdrive be automatically determinedby a. governor, but that the shift to overdrive gear not becompleted'until the operator decides. This result is had in present dayarrangements by' positive dog clutches controlled by solenoids andblocker arrangements. However, a time interval must elapse during whichthe engine decelerates before the shift is completed.V The result isthat rif the driver becomes impatient of the time delay he can, andgenerally does, accelerate before the shift is completed. This situationis annoying at times and undesirable.

It is also desirable that a lock up arrangement be provided for theoverdrive unit, of the type described above, so that the engine can Vbestarted by pushing the car. This is done on present day installations bydental clutches operated by a secondary control through the agency of along Bowden wire Vand an operating button on the dashboard of thevehicle.

The results referred to above are accomplished by the means illustratedin Fig. 6. erence numeral 213 designates a conventional electricalgovernor driven by a pair of gears 219, 220 from the output shaft 77"(or 77) at the rear end of the synchromesh transmission. This governoris set to operate Yat any predetermined speed, say from twenty-thirtymiles per hour, as thercase may require, to set the system for Anautomatic switch 221 is provided which has its contacter 222mechanically conoverdrive operation.

The contacter 222 is connected by -a lead 225 with i the ground terminalof solenoid 179 (or solenoid 127 and a lead 226 connects switchcontact223 with a contact arm 227 of governor 21S. This arm is adaptedto complete a circuit through a governor terminal 228, as a resultof,its mechanical movement from gears 219, 220 when a predetermined, setshift over speed is reached.

A grounded battery 229 has a supply lead 230 electrically `connectingthe same with a iixed contact V231 and with a relay coil 232 mounted ona iixed support 233. A conducting armature 234 forrelay 232 isappropriately pivoted for coaction with the relay coil. It is connectedthrough lead 236 with the contact 228 of governor 21S.

Armature 234 has an insulating blockV 237 thereon which carries acontact 235 adapted to engage Vthe fixed; battery-connected Contact 231when the armature is drawn in clockwise direction by relay 232. Contact23S is connected through lead 240-with the hot terminal of Y solenoid 179.

and is `grounded at 248. Switch button 247 Yis adaptedy to vb ,eactuated by one arm of a bell crank 249 rnedially pivotefd at 250 on theoorboard of the vehicle.Y A link 251 and coil spring 252 normally urgethe bell crank in in that gure, the ref-y clockwise direction. The otherarm of bell crank 249 is operated through a connecting link 251 by theaccelerator pedal 252 of the vehicle, which is pivoted to the oorboardat 253. The purpose of these mechanical connections will appear afterfurther description of the character and operation of electrical unitswhich are controlled thereby. Y

The second xed contact 243 with which the swinging Contact 241 coacts isconnected by a lead 254 with a terminal 256 of a normally closed toggleswitch 257. Switch 257 is in closed condition in the positionillustrated in Fig. 6, in which it engages the upper ange of a channelelement 258 which is bracket-supported on the floorboard of theautomobile. Switch 257 is pivotally supported on the pedal-operated armof bell crank 249, so that when the pedal 252 is thrust down past thefull open throttle position `the toggle switch strikes the lower flangeof channel element 258, being thus tilted to an open position. Thesecond terminal of switch 257 is grounded.

The' second contact '243 of the two xed contacts 242, 243, in additionto being electrically connected with switch 257, is electricallyconnected, in parallelV with that connection, through a lead 260 to thesecond contact 224 of switch 221.

Toggle switch 257 is so arranged that when the throttle pedal 252 isoperatedvnormally during the operation of the vehicle the switch, incircuit-closing condition, travels back and forth in the space betweenthe upper and lower ilanges or arms of channel element 258. When thethrottle is closed, a button on the switch contacts the upper ange,restoring the switch to normal closed condition in the event it has beenopened. On a 'downstroke of pedal 252 past wide open throttle positionanother button on switch 257 strikes the lower flange of element 258.This opens the switch, in which open condition the switch remains duringfurther back and forth operation between the flanges of element 258until the throttle is closed. The switch is then reclosed in the mannerdescribed. Y

Normally open switch 246 only closes when the throttle is fully closed,i. e., when pedal 252 is fully raised, at whichv time bell crank 249engages and actuates button 247, thus to close the switch and allowcurrent to ow through leads 245 and 248 to ground.

An understanding of the operation of the modified governor shift controlsystem just described can best be conveyed by a4 description. of atypical series of manipulations attending the usual, day to day use of amotor vehicle in which the assemblyy is installed. Assuming that anoperator is taking the automobile out of the garage, he first turns onthe ignition and steps on the starter. At this time brake band 166 isalready riding drum 148 and the overdrive unit is in locked position,but the transmission 141 is in neutral position. The

engine is cranked by the starter to running condition.

Incidentally, the fluid coupling makes it possible to so crank theengine even if it is in gear at the transmission.

After the engine has warmed up properly, the driver, by applying brakeband 167 to the associated drum 154, inthe manner described inconnection with Fig. l, halts the coupling-driven overdrive shaft fromrotation under hydraulic drag during the idling period. The driver maythenA manually engage Ytransmission. 14 in either forward or reverseratio, as desired. For the purpose of this illustration, it will. beassumed that the vehicle is to move forward and is thus engaged by thedriver in low gear at transmission14', by the means shown in Fig. 1A.The vehicle moves. forward at low speed. Only a low gear shifter. 261 isshown, howeverV the invention contemplates automatic switch control by aplurality of Shifters as well..

As mentioned above,.movement of a shifter fork of transmission 14mechanically governs movement of the contactor 222 of switch 221. As thelast fraction of an inch of transmission gear shift movement iscompleted, contacter 222 is thus operated to preset the ground circuitof solenoid 179l through lead 225, contact 224 (as shown in dottedline), lead 260, lead 254 and normally closed toggleA switchv 257 (intheposition of the latter illustrated in Fig. 6). It will be observed thatthe circuit through the governor is interrupted as a safety or emergencyfeature of operation in this gear ratio.

Switch 221 is of a partially automatic character, being so arranged andinterlocked with the selector lever or levers of transmission 14'-, orthe forks controlled thereby, that its contacter 222 is returnedtoaneutral point 223 on the switch body and remains at that point just assoon as the transmission is shifted out of gear and into neutral, aswill be later described. In low, intermediate and reverse gear ratiosthe contacter engages Contact 224, as described.

When the operator reaches a speed at which he wishes to engage thetransmission 14 in high gear he manipulates the transmission selectorlever to high gear position. Through the mechanical connection of thetransmission selector or shifter to switch contacter 222, the lattermakes contact with the contact 223 in its last fraction of an inch oftravel, as shown in solidline-in Fig. 6. A ground circuit is thuspartially established for solenoid 179 through lead 225, contacter 22,2,contact 223 and lead 226 to governor contact arm 227. lf at this timethe governor 218 has reached the critical speed for shift to overdrive,governor contact arm 227 is caused to engage its fixed contact 228. Ifthe governor has not yet reached overdrive speed when transmission 14 isshifted to high, and assuming that the driver is accelerating the car,the latter remains in direct drive. As soon as the governor contacts227, 228 are closed upon attainment of the critical speed, the circuitfor solenoid 179 would normally further be completed through the lead236, conducting armature or arm 234 of relay 232 contacts 241 and 242,lead 245,- switch 246 to lead 248 and ground. However, since it has beenassumed that the driver is accelerating the car, the solenoid circuitjust described is seen to be interrupted at normally open switch 246,due to disengagement of bell crank 249 from the operating button 247 ofthat switch.

Hence closing of governor contacts 227, 228 will have no eect and thedriver will continue to proceed indirect drive as long as he is holdingdown accelerator pedal 252. When he decides to place unit 13' inoverdrive, assuming the governor 218 is still at or above a criticaloverdrive speed, the driver merely needs to release pedal 252', closingthe throttle, whereupon the solenoid circuit is completed throughthrough then energizing closed switch 246 and an energizing circuitportion including the connections recited above to energize solenoid179.

Relay 232 is energized at the same instant, shifting the solenoid groundcircuit through an engagement of armature contact 241 with iXed contact243, rather than with xed contact 242. This transfers control of thesolenoid to toggle switch 257 and a holding circuit portion includingthe same. The solenoid energizing circuit is further shifted, uponenergization of relay 232, by engaging the contact 238 (carried on butinsulated from armature 234) with the fixed, battery-connected contact231. Solenoid 179 now operates through the hydraulic mechanism describedabove to actuate brake band and halt drum 148, thus placing overdriveunit 13 in overdrive position.

In this condition,v as long as the driver operates the car in a normalmanner above the critical overdrive speed of governor 218, the relay 232and solenoid 179 will remain energized and overdrive will continue.However, if at any time the driver wishes to overrule the overdrive andreturn to direct drive, he need only depress; accelerator 252' past itswide open throttle position. Bell crank 249 then carries toggle switch257 downwardly to the dotted line position of Fig. 6, in whichit'engages the lower tlange ofthe channel member 258, opening the groundcircuit of Ysolenoid 179 at the open switch. The solenoid isV therebyde-energized, as well as relay 232.V While remaining in high gear, thetransmission14 returns to direct drive through unit V13'. l

Restoration of overdrive ,is' accomplished by simply fully elevating theVpedal 252', thereby `causing vswitch 246 to close, with resultantenergization of solenoid 179 and relay 232, as at original setting.However, at this time switch 257 also contacts the upper iiange ofmember 258, causing it to be closed and transfer ground of the relayfrom energizing switch 246 to holding switch 257.-A

In the event the vehicle decelerates to a point where governor 218separates contact 227, 22S, the brake band 166 is immediately releasedby interruption of the solenoid circuit.Y Direct Vdrive then takes placethrough the unit 13. e

In the furtherV event that the driver is in a deep climb upgrade, taxingthe full capacity .of they engineand` calling for the lowest ratioavailable, the driver may shift transmission 14' into low gear but holdits selector-lever from its full detent position, so that contactorY 222of switch 221 is caused to remain at the intermediate, neutral position223'. The result is that a full, low transmission ratio,without'overdrive in the unit'13, is available. it is desirable inascending a difficult incline that the engine be placed back in the nextratio as soon as sufficient momentum has been attained.' To do this, thedriver simply allows the transmission gear selector lever to return toits detent position, which enables brake band 166 to be applied to drum148A. This places the overdrive in effect and thus achieves a powershift` of one ratio higher, upon which further climb may be continued.It isse'en that a split ratio between low and second gear is thusaccomplished without power interruption.

Figs. 8, 9, l and 10A illustrate a proposedarrange- Vment for shitingthe contacter 222 of switch 221 in response to operation of the selectormeans of transmission 14 (or 14'), which is Vdepicted as having twoselector levers controlling three forward and one reverse ratios. Thereference numerals 262 and 263 designate the respective selector levers,each of which is keyed to a shaft 264 by which the operation of theshifterforks of the transmission is accomplished. It is not rdeemednecessary to illustrate the shaft-shifter fork connection further thanas depicted in Fig. 1A, since the arrangement is entirely conventionalin this respect and will be readily understood by those skilled in theart. Levers 262, 263 are each provided with a segmental rearextension265 which carries an upwardly facing, shaped cam surface, designated 266in the case of the lever 262 and 267 in the case of the lever 263. Asheet metal or equivalent channel shaped switch control arm 268 ispivoted at 269 on a suitable iixed support, this arm being provided withopposed downwardly depending cam follower anges 270, 271. It is urged bya coil spring 272 in a direction tending to engage` anges with the cams266, 267, respectively;

The cam 266 on lever 262, which controls second or intermediate speedand high speed ratios, is shaped toV provide a depression 273 and, inspaced relation tothe right thereof, a rise 274. The cam is flat in theportion 275 between the depression and rise. Theother cam 267, whichcontrols reverse and low speed ratios, is equipped with rises 276, 277at opposite ends thereof and with a depression 278 midway therebetween.`Cam 267 is flat in the zones between depression Y278 and rises 276, 277,

respectively. I Y y i' A forwardly projecting terminaltongue 280 on arm268 (see Figs'. 8 and 9) is provided with Yan upwardly projecting button 281 which is invertical valignment with .a contact button .282carried on the contacter y222 of L3 Vswitch 221. The contacter is urgeddownwardly bya Vspring 283. A Y y VWhen the-transmission selector levers262, 2,63 are in neutral position with the midpoints ofr cams 266,;267disposed beneath the respective flanges 270,271 asshown in Fig. 10, thefollower ange 270 on arm 263Arides the flat, intermediate neutralportion of cam V266 andthe op- Y posite follower flange 271 is thus heldsuspended over the central depression 27S of the other cam 26,7. If theselector lever 263 is now shifted to low speed position, i. e.,counterclockwise in Fig. 9 and to the left inFigs. l0 and 10A, the iiatportionoffcam 267 to the right of depression 27S travels beneathfollower ange 271'until the iinalincrement of selector movement. As thismovement x (Fig. l0) is completed, cam rise l277 passesunder ange 271and lifts arm 26S from its neutral position, as shown in dotted line inFig. l0. Button 2S1Ycontacts switchV button 282 and raises contacter2,22 from a neutral position, yin which it has been held in engagementwith contact 223' by the cam ilat, into engagement with the contact 224.The same effect takes place when arm 263 is shifted in the oppositedirection from neutral to reverse gear position.v

In this casefcarn riseY 276 raises arm268. `In either of these twospeeds the possibility of completion of an electrical circuit throughgovernor 218, and placing ofthe system in voverdrive condition,isprevented.

V When the intermediate-high speed selector leyer 262 is manipulatedtosecond speed position, i. e., counterclockwise in Fig. 9 and'to the leftin Figs. 10 andlOA, cam rise 274 has the samel effect of elevating arm268 Yand Y engaging contacter 222 with contact 224.l The safety lock-outof the overdrive obtains in this speed also.v When lever 262 is shiftedoppositely Vto high speed position,'cam depression 273 comes intoalignment, in the last increment of travel of the lever, with followerange 270, as indicated in Fig. 10A. Since lever 2673 is in neutralposition, the follower flanges V270, 271 are now aligned with camdepressions 273, 278, respectively. Switchcontacter 222 is lowered intoengagement with contact 223, whereupon control is again turned over tothe governor 218.1 Y

The above described type of automatic governor cut-in and lock-outoperation from the transmissionA is also adapted for association withtransmissions having more or less than two selector members by anobvious simplilication or multiplication ofthe means shownV invFigs. 8through 10A. i

l claim: g

1. A transmission system comprising an l,engine Ydriven coupling unit, achange speed unit and a manually controll able transmission unitdrivingly `connected to one another,

an electrically energizable control unit operatively connected to saidchange speed unit'to actuate the same for change speed action,l andmeans controlling said control unit, including an engine drivengovernor, and an electrical circuit independent of the ignition circuitof saidV engine connected tosaid control unit and said governorandcompleted through the latter to energize the control unit, saidcircuit comprising a change speed unit energizing portion and a changespeed unit holding portion, a switch in said energizing circuit portionoperable to complete the same,

a further switch in said holding circuit portion operable.Y

to completeV and to overrule said holding portion notwithstandinguninterrupted ignition operation `of said engine,A and a manuallyactuable operating member common to Y annesse :Controlled actuating`,device for said Ineens, n aovrernor switch operatively connectedtosaid transrnission unitand controlled byoperation of said selectordevice, afurther switch automatically controlled by said governor, andmeans to complete energizingandholding circuits for said device uponclosing of saidy governor controlled switch and s aid transmissioncontrolled switch, said last named means including differentenergizingand holding switches and a common control devicethereforhaving mechanical means operatively connected to therespectiveSwitches to open said holding switch and overrule said holding `circuitatthe option of an operator of said systemnotwiths'tand ,unit driven byanignition controlled-engine,tantfengine driven governor, anenginedriven source of pressureffiuid delivering the same ata predeterminedpressure, and means to control suchchange speed unitthrough vs aidAgovernor, comprising aiiuid pressure actuated Vmember operativelyconnected to said change speedu nit an d ,actuated only by pressure inexcess of said predetermined delivery pressure, a pressure boosterdeviceconnectedto said source and member and operating to boost thede- Aliverypressure of the former to a value requisite to operate the latter, anelectrically controlled actuating device for said booster device, andanelectrical control circuit separate and distinct from the ignitioncircuit of said engine for said actuating device,.s aid circuit includinga switch automatically controlled by said governor, and

` electrical connections .to completeV an energi2ifr1. Circuitforsaidactuating device 'through said governorcontrolled switch atapredetermined governor speed.

5. A transmission system comprising a vchange speed .unit driven ,byanignition controlled engine, a n engine drivengovernor, an engine drivenSource of. pressnre'nid Ydeliyering V the same ,at a predeterminedpressure, and means 'to ,control .Sneh change speed nuit, ,through ,saidgovernor, comprising a fluid pressure Yactuated memberoperativelyconnected to said change speed unita'nd actuated onlybypressureinexcess of said predetermined delivery pressure, a pressurebooster device counectedro said source and member and operating Vtoboost th` e de livery pressure of the vformerto a value requisite tooperate the latter, an electrically controlled actuating'deviceforsaidbooster device, a nd an electricalcontrolcir- .c separatetanddsltnetfrom.thegignitioncircuitofsaid 'engine torvtseid-ectnating devicesaid circuit including a svvit'ch 'automatically controlled by saidlgoverr1or, and ,eleeuieal eonneetonsto complete anenersifzing eirentfor.said ,actuating Vdevice through .Seidfgovernor-eontrolled ys vyitch ata prede term ined governor speed,.s aid connectionsinelndins manuallycontrolled switch. means-.torontpleteor .interrupt said energizingcircuitat the option oan operator of seid. System notwithstandingcontinued uninterrupted operation of saidengine.

6. A transmission system comprisingan engine dr'iyen changespeed unit, amanually controllable y transmission' unit driven by Seid ehenseepeedunit. an. ensineldnven governor, an. engine driven ,source of pressurer'1i d, de live-ring the. 'same .at a predetermined pressure and ineensto controljsaidchange speed `unit through 'said governor, comprising auid pressure. actuated member operatively connected to said change`speed -unit and actuated only by pressure in excess of saidpredetermined'deliverypressure, a pressure booster device connected to sa i d 'source and 'memberand operating to boost 'thedeliyerypressure ofthe formerto a value requisiteto operatethe latter, Van electricallycontrolled actuating device` for aid booster device,k and an electricalcontrol circuit'fon said actuating device, said cir'cuitjbeing operativeindependently of a nd without atect to the electrical circuit of said,engineand including a switchoperatively connected to said transmi'ssionunit and controlled by operation of the latter, a 'further switchautomatically controlled by said governor, and electrical connections tocomplete an energizing circuit for said actuating device through ,said

goyernorand transmission-controlled switches at a predetermined governorspeed and predetermined setting of sjajid transmission unit, .saidconnections including manually controlled switch means to complete orinterrupt said energizing 'circuit at the option of an operator of saidsystem.

YA7.5A power vtransmission system comprising a change speedunit'driveneby a prime mover, hydraulicV pressure .operated means tocontrol the unit including a lowpressure chamber, and a hydraulicallya'ctuable control plunger mov'ablettherein and operatively connect'edtosaid change speed unit, said ,plunger operating under a predeterminedhydraulic-pressure to control said unit, hydraulic pres- 'sur'e supplymeans driven by said prime m'overandnormallydelivering pressure liquidat a relatively low pressure less ,than said predetermined operatingpressure for said control plunger, and a booster. device operativelyconnected '.between said pressure supply Vmeans and said low pressureVchamber to boost said normal `delivery pressure of the former tothevalue requisite to actuate said plunger, said booster device comprisinga Vbooster cylinder having aplunger'bore'between the same and said low4pressure chamber, a plunger slidablel in said bore, said'last named.plunger being provided vwith an enlarged head slidably engaging. saidbooster cylinder andtdeiining a pressure chamber therein on 'the side of'said plunger fhead remote fromsaid bore, -a common hydraulic supplyline connecting said low Ypressure chamber andsaid cylinder pressurechamber with said normally low pressure hydraulic supply means, andayi`eldable pressure responsive valve in said 'linecontrollingcommunication of said `cylinder pressurechamber therewith, saidV irstnamed plungerbeing initially actuable under low pressure from said lineand upon an increase in pressure iny said'line said booster cylinderVpressure: chamber being opened thereto, whereby said last Vnamedplungeryis 'advanced through said bore toward'said low pressurechamberto further and substantially intensify -the pressure Vin the flatter.

'8. YAn assembly in accordancewith 'clamjlin which said hydraulic supply'line includes said bore and is sealed off at said bore and between saidpressuresupply means and lowV pressure chamber byr advance of said,plunger in said "bore.

=9. vApower transmission system comprising a change speed unit 'drivenby a prime mover, hydraulicipressure operated meansto control the unitincluding a' hydraulically actuable control device operativelyconnecte/d to -said unit to control the same and operatingl under LaTpredetermined hydraulic pressure, hydraulic pressuresupply means tooperate said control vdevicefincludirig V annit `driven by said primemover and Anormally delivering pressure liquid to said device ata'pressureless than saidpredetermined operating pressure 'for saidlcontrol device, and a booster device operativelyconnected'to andbetween saidY pressure supply unit and control device to boost saidnormal delivery pressure of the, former to the value requisite toactuate 'the latter, said control )device comprising a pressureresponsive plunger .operatively connected to said change speedunitandinitially to `said normal delivery pressure, and communicatingVgovern change speed action of said change speed unit,

cheese of liquid by said hydraulic supply unit'toY said'rst namedplunger.

Y 10. A power transmission system comprising an engine driven unit, achange speed unit" driven by said engine driven unit, a manuallycontrollable' transmission unit driven by said change speed unit, andcontrol means to governrchange speed'action of said changeV speedunit,

'said control means including hydrualic pressure Vresponsive means todirectly govern change speedraction, hy-

` draulic pressure. supply means driven by s'aiden'gine driven unit tooperate said pressure responsive means, and

'v electrically operable means to control the operation of said pressureresponsive means, said electrically operable means including a governorand associated wiring circuit electrically separate and independent'ofthe ignition cir-l cuit of said engine driven unit, circuit Ycontrollingmeans actuated by the manual control of said transmission unit, andmanually controlled switches in said eircuitV to regulate the operationof energizing and holding portions of vsaid circuit affecting theoperation of said pressure responsive means notwithstanding continueduninterrupted operation of said engine driven unit.V 'i v 11.`A powertransmission systerrrcomprisingY an engine driven unit, a change speedunit driven by said engine driven unit, a manually controllabletransmission unit driven by said change speed unit, and control means togovern change speed action of said change speed unit, said control meansincluding (hydraulic pressure `responsive means to directly governchange speed action, hydraulic pressure supply means driven by saidengine hydrualic pressure booster means associated with said supplymeans in the operation of said pressure responsive means in response tocompletion of initial operative response of said pressurerresponsivemeans to said supplyy means, and electrically operable means to controlthe 'operation of said pressure responsive means, said electricallyoperable means including a governor'and associated wiring circuitelectrically separate and independent of the ignition circuit of saidengine driven unit, circuit con trolling means actuated by the manualcontrol of'said transmission Yunit, and manually controlled switches insaid circuitrrto regulate the Yoperation of energizing and holdingportionsl of said circuit atecting the operation of said pressureresponsive means notwithstanding con- ,i tinued uninterrupted operationof said engine driven unit.

12. A power transmission system comprising an engine driven unit, achange speed -unit driven by said engine driven unit, a manuallycontrollable transmission driven unit to operate said pressureresponsive means,

unit driven by said change speed unit, control means to (M.

hydraulic pressure supply means to operate said control means includinga unit driven by said engine driven unit Aand normally deliveringpressure liquid to `said control means at a pressure less than apredetermined operating pressure for said control means, said controlmeans comprising Va pressure responsive plunger operatively associatedwith said change speed unit and initially operable rby liquid suppliedat normal .delivery pressure by said hydraulic vpressure supply means, afurther' I and actuable thereby to further compress said liquid"operating said irst named plunger, and pressure responsive means lforcontrolling the actuation of vsaid further plunger in response tocompletion of operative response ofsaid first named plunger, andelectrically operable means to control the `operation Vof Asaid control"means, said electrically noperable means including a governor andassociated wiring circuit'relectrically separate and Y, imdependent ofthe ignition circuit of said engine driveny 75 'trolledswitch andcontinued operation of said engine, said unit,` circuitcontrollingrmeans actuated by the manual control of said transmissionunit, and manually controlled switches in said circuitl to regulate 'theoperation of energizing and holding portions ofssaid circuit atectingthe opcrationrof said control means notwithstanding continueduninterrupted operation of said engine driven'unit.

13. A power transmission system lcomprising an engine driven couplingunit, a change speed'unit and a manuallyV controllable transmission unitdrivingly connected to one another, an electrically energizable controlunit operatively connected to said change speed unit to actuate the samefor change speed action, and means controlling said control unit,including an enginedriven governor, and an electrical circuitindependentof the igition circuit of said engine connected tosaidcontrolchange speed unit, a manual-selector device to control V saidtransmission unit, means operatively connected to said change speed unitto control the same, an electrically controlled actuating device forsaid means, a governor i driven by an ignition controlled engine, and anelectrical control circuit independent of the ignition circuit of saidengine for saidvactuating device, said circuit including ai f switchoperatively connected to said transmission unit and controlled byoperationk of said selector device, a further Vswitchautomaticallycontrolled byV said governor means to complete energizing and holdingcircuits for said device upon closing of rsaid governor controlledswitchV and saidtransmission controlled switch, said last named meansincluding diierent'energizing Vand holding switches and a common controldevice therefor having mechanical means operatively connected toftherespectiverswitches to open said holding switch and overrule saidholding circuit vat the option of an operator notwithstanding closing ofsaid transmission controlled switch and governor controlled switch andcontinued operation of said engine, saidme-V chanical means operablewith said energizing.,switchrteV initially complete said energizingcircuitrto bring about energization of said holding circuit, saidholdingcircuit being operable independently of said energizingcircuitupon the initial energization thereof Yuntil manually overruled by saidoperator. Y. Y Y t f 15. YIn combination,` a change speed unit,armanually controllable transmission unit drivingly connected to saidchange speed unit, a manual-selector device to control saidYtransmission unit, means operatively connected to4 said vchange speedunitV to controlthe same, an electrically controlled actuating devicefor Ysaid meansa governor driven by an ignition controlled engine, andan electrical controlV circuit independent of theignition circuit orVsaid engineV for said actuating device,V said circuit'including a switchoperatively connected to. said transmission unit andfco'ntrolled byoperation of said selector device, afurther switch automaticallyYcontrolledV by. saidgovernor, and

Vmeans to complete energizingand holding circuits for Y said device uponclosing of said 'governor controlled 'switch and said transmissioncontrolledfswitch,v said last named means including dierenty energizingand holdingtswitches vand acommon control device -therefor havingVmechanical means operatively connected tothe respective switchesI toopen said holdingY switch andoverrulesaid holding circuit at,theroptionof an operator notwithstanding closing of said transmissionYcontrolled :switch and governor vconmechanical means including cammingmeans one of which is operable with said energizing switch to initiallycomplete said energizing circuit to bring about energization of saidholding circuit in combination with the action of further camming means,said holding circuit being operable independently of said energizingcircuit upon the initial energization thereof until manually overruledby said operator.

16. A power transmission system comprising an engine driven couplingunit, a change speed unit and a manually controllable transmission unitdrivingly connected to one another, an electrically energizable controlunit operatively connected to said change speed unit to actuate the samefor change speed action, and means controlling said control unitincluding an engine driven governor, and an electrical circuitindependent of the ignition circuit of said engine connected to saidcontrol unit and said governor and completed through the latter toenergize the control unit, said circuit comprising a change speedenergizing portion and a change speed holding portion, means in saidenergizing circuit portion operable to electrically complete the same,further means in said holding circuit portion operable to complete andto overrule said holding portion notwithstanding the continued operationof said engine driven coupling unit, and a manually actuable operatingmember associated with said means to control the operation of thelatter, said holding circuit portion being operable independently ofsaid .energizing circuit portion upon the initial energization thereofby said 22 energizing circuit portion until overruled by said manuallyactuable operating member.

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